U.S. patent application number 10/096637 was filed with the patent office on 2002-08-08 for method for applying uniform pressurized film across wafer.
Invention is credited to Blalock, Guy T., Carroll, Lynn J., Stroupe, Hugh E..
Application Number | 20020106899 10/096637 |
Document ID | / |
Family ID | 24610247 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020106899 |
Kind Code |
A1 |
Blalock, Guy T. ; et
al. |
August 8, 2002 |
Method for applying uniform pressurized film across wafer
Abstract
A method of manufacturing semiconductor devices using an
improved planarization process for the planarization of the
surfaces of the wafer on which the semiconductor devices are
formed. The improved planarization process includes the formation
of a flat planar surface from a deformable coating on the surface
of the wafer using a fixed resilient flexible material member
contacting the wafer.
Inventors: |
Blalock, Guy T.; (Boise,
ID) ; Stroupe, Hugh E.; (Boise, ID) ; Carroll,
Lynn J.; (Middleton, ID) |
Correspondence
Address: |
TRASK BRITT
P.O. BOX 2550
SALT LAKE CITY
UT
84110
US
|
Family ID: |
24610247 |
Appl. No.: |
10/096637 |
Filed: |
March 12, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10096637 |
Mar 12, 2002 |
|
|
|
09650779 |
Aug 29, 2000 |
|
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Current U.S.
Class: |
438/691 ;
257/E21.242; 257/E21.244; 257/E21.245 |
Current CPC
Class: |
H01L 21/31055 20130101;
H01L 21/31058 20130101; B24B 37/30 20130101; H01L 21/31053
20130101 |
Class at
Publication: |
438/691 |
International
Class: |
H01L 021/302 |
Claims
What is claimed is:
1. An apparatus for the planarization of a surface on a wafer, said
apparatus comprising: an object having an upper surface, lower
surface, and outer diameter, the object located above said wafer;
and a resilient flexible material member located below the lower
surface of the object for supporting said wafer thereon, said
resilient flexible material member having a variable deflection to
an application of force thereto.
2. The apparatus of claim 1, further comprising a lid assembly, the
lid assembly including the object therein.
3. The apparatus of claim 1, further comprising a lid assembly
including: an upper lid; a middle lid having an upper surface,
lower surface, inner surface, and outer surface, the middle lid
located between the upper lid and a lower lid; and the lower lid
having a portion thereof located below the lower surface of the
object.
4. The apparatus of claim 3, further comprising an interface clamp
retaining a portion of the resilient flexible material member
between the lower lid and the interface clamp.
5. The apparatus of claim 4, further comprising an annular seal
sealingly engaging a portion of the object and a portion of the lid
assembly.
6. The apparatus of claim 3, wherein the lower lid includes a
plurality of apertures therein.
7. The apparatus of claim 3, further comprising a chamber located
below the lower lid.
8. The apparatus of claim 3, further comprising a plurality of
fasteners retaining the upper lid to the middle lid.
9. The apparatus of claim 7, further comprising a plurality of
fasteners retaining the lower lid to the chamber.
10. The apparatus of claim 4, further comprising a plurality of
fasteners retaining the interface clamp to the middle lid.
11. The apparatus of claim 3, wherein the upper lid comprises a
generally cylindrical annular member having an upper surface, inner
diameter surface, lower surface, outer diameter surface, and a
plurality of apertures extending from the upper surface to the
lower surface.
12. The apparatus of claim 3, wherein the lower lid comprises a
generally cylindrical annular member having an upper surface, first
vertical inner cylindrical surface, inner annular surface,
cylindrical surface, bottom surface, outer cylindrical surface, and
a plurality of apertures for receiving portions of fasteners
therein.
13. The apparatus of claim 3, wherein the middle lid comprises a
generally cylindrical annular member having an upper surface,
frusto-conical annular inner surface, inner cylindrical surface,
first cylindrical annular surface, first vertical outer diameter
surface, second cylindrical annular surface, second vertical outer
diameter surface, at least one aperture for supplying a gas
therethrough, and at least one annular seal for sealingly engaging
a portion of the object, the middle lid located between the upper
lid and the lower lid.
14. The apparatus of claim 3, wherein said resilient flexible
material member has a substantially uniform thickness.
15. The apparatus of claim 3, wherein said resilient flexible
material member has a substantially uniform thickness having
portions thereof having differing resilient properties.
16. The apparatus of claim 3, wherein said resilient flexible
material member has a substantially uniform thickness having
portions thereof having differing durometer hardness
properties.
17. The apparatus of claim 3, wherein said resilient flexible
material member has a variable thickness.
18. The apparatus of claim 3, wherein said resilient flexible
material member has a variable thickness having portions thereof
having differing resilient properties.
19. The apparatus of claim 3, wherein said resilient flexible
material member has a variable thickness having portions thereof
having differing durometer hardness properties.
20. A planarization apparatus for use on a surface on a wafer, said
apparatus comprising: an object having an upper surface, lower
surface, and outer diameter, the object located above said wafer;
and a resilient flexible material member located below the lower
surface of the object for supporting said wafer thereon, said
resilient flexible material member having a variable deflection to
an application of force thereto.
21. The apparatus of claim 20, further comprising a lid assembly,
the lid assembly including the object therein.
22. The apparatus of claim 20, further comprising a lid assembly
including: an upper lid; a middle lid having an upper surface,
lower surface, inner surface, and outer surface, the middle lid
located between the upper lid and a lower lid; and the lower lid
having a portion thereof located below the lower surface of the
object.
23. The apparatus of claim 22, further comprising an interface
clamp retaining a portion of the resilient flexible material member
between the lower lid and the interface clamp.
24. The apparatus of claim 23, further comprising an annular seal
engaging a portion of the object and a portion of the lid
assembly.
25. The apparatus of claim 22, wherein the lower lid includes a
plurality of apertures therein.
26. The apparatus of claim 22, further comprising a chamber located
below the lower lid.
27. The apparatus of claim 22, further comprising a plurality of
fasteners retaining the upper lid to the middle lid.
28. The apparatus of claim 26, further comprising a plurality of
fasteners retaining the lower
29. The apparatus of claim 23, further comprising a plurality of
fasteners retaining the interface clamp to the middle lid.
30. The apparatus of claim 22, wherein the upper lid comprises a
generally cylindrical annular member having an upper surface, inner
diameter surface, lower surface, outer diameter surface, and a
plurality of apertures extending from the upper surface to the
lower surface.
31. The apparatus of claim 22, wherein the lower lid comprises a
generally cylindrical annular member having an upper surface, first
vertical inner cylindrical surface, inner annular surface,
cylindrical surface, bottom surface, outer cylindrical surface, and
a plurality of apertures for receiving portions of fasteners
therein.
32. The apparatus of claim 22, wherein the middle lid comprises a
generally cylindrical annular member having an upper surface,
frusto-conical annular inner surface, inner cylindrical surface,
first cylindrical annular surface, first vertical outer diameter
surface, second cylindrical annular surface, second vertical outer
diameter surface, at least one aperture for supplying a gas
therethrough, and at least one annular seal for sealingly engaging
a portion of the object, the middle lid located between the upper
lid and the lower lid.
33. The apparatus of claim 22, wherein said resilient flexible
material member has a substantially uniform thickness.
34. The apparatus of claim 22, wherein said resilient flexible
material member has a substantially uniform thickness having
portions thereof having differing resilient properties.
35. The apparatus of claim 22, wherein said resilient flexible
material member has a substantially uniform thickness having
portions thereof having differing durometer hardness
properties.
36. The apparatus of claim 22, wherein said resilient flexible
material member has a variable thickness.
37. The apparatus of claim 22, wherein said resilient flexible
material member has a variable thickness having portions thereof
having differing resilient properties.
38. The apparatus of claim 22, wherein said resilient flexible
material member has a variable thickness having portions thereof
having differing durometer hardness properties.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application is a divisional of patent application Ser.
No. 09/650,799, filed Aug. 29, 2000, pending, which is related to
U.S. patent application Ser. No. 08/862,752, filed May 23, 1997,
entitled "Planarization Process for Semiconductor Substrates."
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to the manufacturing of
semiconductor devices. More particularly, the present invention
relates to an improved method and mechanism using a resilient
flexible material member under a wafer during wafer processing for
the planarization of surfaces in the manufacturing of a
semiconductor.
[0004] 2. State of the Art
[0005] Typically, integrated circuits are manufactured by the
deposition of layers of predetermined materials to form the desired
circuit components on a silicon wafer semiconductor substrate. As
the layers are deposited on the substrate wafer to form the desired
circuit component, the planarity of each of the layers is an
important consideration because the deposition of each layer
produces a rough, or non-planar, topography initially on the
surface of the wafer substrate and, subsequently, on any previously
deposited layer of material. Typically, photolithographic processes
are used to form the desired circuit components on the wafer
substrate. When such photolithographic processes are pushed to
their technological limits of circuit formation, the surface on
which the processes are used must be as planar as possible to
ensure success in circuit formation. This results from the
requirement that the electromagnetic radiation used to create a
mask, which is used in the formation of the circuits of the
semiconductor devices in wafer form, must be accurately focused at
a single level, resulting in the precise imaging over the entire
surface of the wafer. If the wafer surface is not sufficiently
planar, the resulting mask will be poorly defined causing, in turn,
a poorly defined circuit which may malfunction. Since several
different masks are used to form the different layers of circuits
of the semiconductor devices on the substrate wafer, any non-planar
areas of the wafer will be subsequently magnified in later
deposited layers.
[0006] After layer formation on the wafer substrate, either a
chemical etch-back process of planarization, a global press
planarization process typically followed by a chemical etch-back
process of planarization, or a chemical mechanical planarization
process, may be used to planarize the layers before the subsequent
deposition of a layer of material thereover. In this manner, the
surface irregularities of a layer may be minimized so that
subsequent layers deposed thereon do not substantially reflect the
irregularities of the underlying layer.
[0007] One type of chemical etch-back process of planarization,
illustrated in EUROPEAN PATENT APPLICATION 0 683 511 A2, uses a
coating technique in which an object having a flat surface is used
to planarize a coating material applied to the wafer surface prior
to a plasma reactive ion etching process being used to planarize
the wafer surface. Often, however, the planarization surface will
contain defects, such as pits or other surface irregularities.
These may result from defects in the flat surface used for
planarizing or from foreign material adhering to the flat surface.
The etching of such a wafer surface having irregularities will, at
best, translate those undesirable irregularities to the etched
surface. Further, since some etching processes may not be fully
anisotropic, etching such irregular surfaces may increase the size
of the defects in the etched wafer surface.
[0008] One type of global press planarization process, illustrated
in U.S. Pat. No. 5,434,107, subjects a wafer, with features formed
thereon having been coated with an inter-level dielectric material,
to an elevated temperature while an elevated pressure is applied to
the wafer using a press until the temperature and pressure
conditions exceed the yield stress of the upper film on the wafer
so that the film will attempt to be displaced into and fill both
the microscopic and local depressions in the wafer surface. It
should be noted that the film is only deformed locally on the
wafer, not globally, during the application of elevated temperature
and pressure since the object contacting the surface of the wafer
will only contact the highest points or areas on the surface of the
wafer to deform or displace such points or areas of material
locally, not globally displace the material on the entire wafer
surface. Other non-local depressions existing in the wafer are not
affected by the pressing as sufficient material is not displaced
thereinto. Subsequently, the temperature and pressure are reduced
so that the film will become firm again thereby leaving localized
areas having a partially planar upper surface on portions of the
wafer while other portions of the wafer surface will remain
non-planar.
[0009] In one instance, global planar surfaces are created on a
semiconductor wafer using a press located in a chamber. Referring
to drawing FIG. 1, a global planarization apparatus 100 is
illustrated. The global planarization apparatus 100 serves to press
the surface of a semiconductor wafer 120 having multiple layers
including a deformable outermost layer 122 against a fixed pressing
surface 132. The surface of the deformable layer 122 will assume
the shape and surface characteristics of the pressing surface 132
under the application of force to the wafer 120. The global
planarization apparatus 100 includes a fully enclosed apparatus
having a hollow cylindrical chamber body 112 and having open top
and bottom ends, 113 and 114, respectively, interior surface 116
and an evacuation port 111. A base plate 118 having an inner
surface 117 is attached to the bottom end 114 of chamber body 112
by bolts 194. A press plate 130 is removably mounted to the top end
113 of chamber body 112 with pressing surface 132 facing base plate
118. The interior surface 116 of chamber body 112, the pressing
surface 132 of press plate 130 and the inner surface 117 of base
plate 118 define a sealable chamber. Evacuation port 111 can be
positioned through any surface, such as through base plate 118, and
not solely through chamber body 112.
[0010] The press plate 130 has a pressing surface 132 with
dimensions greater than that of wafer 120 and being thick enough to
withstand applied pressure. Press plate 130 is formed from
non-adhering material capable of being highly polished so that
pressing surface 132 will impart the desired smooth and flat
surface quality to the surface of the deformable layer 122 on wafer
120. Preferably, the press plate is a disc-shaped quartz optical
flat.
[0011] A rigid plate 150 having top and bottom surfaces 152 and
154, respectively, and lift pin penetrations 156 therethrough is
disposed within chamber body 112 with the top surface 152
substantially parallel to and facing the pressing surface 132. The
rigid plate 150 is constructed of rigid material to transfer a load
under an applied force with minimal deformation.
[0012] A uniform force is applied to the bottom surface 154 of
rigid plate 150 through the use of a bellows arrangement 140 and
relatively pressurized gas to drive rigid plate 150 toward pressing
surface 132. Relative pressure can be achieved by supplying gas
under pressure or, if the chamber body 112 is under vacuum,
allowing atmospheric pressure into bellows 140 to drive the same.
The bellows 140 is attached at one end to the bottom surface 154 of
rigid plate 150 and to the inner surface 117 of base plate 118 with
a bolted mounting plate 115 to form a pressure containment that is
relatively pressurized through port 119 in base plate 118. One or
more brackets 142 are mounted to the inner surface 117 of the base
plate 118 to limit the motion toward base plate 118 of the rigid
plate 150, when bellows 140 is not relatively pressurized. The
application of force through the use of a relatively pressurized
gas ensures the uniform application of force to the bottom surface
154 of rigid plate 150. The use of rigid plate 150 will serve to
propagate the uniform pressure field with minimal distortion.
Alternately, the bellows 140 can be replaced by any suitable means
for delivering a uniform force, such as a hydraulic means.
[0013] A flexible pressing member 160 is provided having upper and
lower surfaces 162 and 164, respectively, which are substantially
parallel to the top surface 152 of rigid plate 150 and pressing
surface 132. Lift pin penetrations 166 are provided through member
160. The flexible member 160 is positioned with its bottom surface
164 in contact with the top surface 152 of rigid plate 150 and lift
pin penetrations 166 aligned with lift penetrations 156 in rigid
plate 150. The upper surface 162 of the member 160 is formed from a
material having a low viscosity that will deform under an applied
force to close lift pin penetrations 166 and uniformly distribute
the applied force to the wafer, even when the top surface 152, the
upper surface 162 and/or the lower surface 164 are not completely
parallel to the pressing surface 132 or when thickness variations
exist in the wafer 120, rigid plate 150 or member 160, as well as
any other source of non-uniform applied force.
[0014] Lift pins 170 are slidably disposable through lift pin
penetrations, 156 and 166, respectively, in the form of apertures,
to contact the bottom surface 126 of wafer 120 for lifting the
wafer 120 off the top surface 162 of member 160. Movement of the
lift pins 170 is controlled by lift pin drive assembly 172, which
is mounted on the inner surface 117 of the base plate 118. The lift
pin drive assembly 172 provides control of the lift pins 170
through conventional means. Lift pins 170 and lift pin drive
assembly 172 are preferably positioned outside the pressure
boundary defined by the bellows 140 to minimize the number of
pressure boundary penetrations. However, they can be located within
the pressure boundary, if desired, in a suitable manner.
[0015] A multi-piece assembly consisting of lower lid 180, middle
lid 182, top lid 184, gasket 186 and top clamp ring 188 are used to
secure the press plate 130 to the top end 113 of chamber body 112.
The ring-shaped lower lid 180 is mounted to the top end 113 of
chamber body 112 and has a portion with an inner ring dimension
smaller than press plate 130 so that press plate 130 is seated on
lower lid 180. Middle lid 182 and top lid 184 are ring-shaped
members having an inner ring dimension greater than press plate 130
and are disposed around press plate 130. Middle lid 182 is located
between lower lid 180 and top lid 184. A gasket 186 and top clamp
ring 188 are members having an inner ring dimension less than that
of press plate 130 and are seated on the surface of press plate 130
external to the chamber. Bolts 194 secure press plate 130 to the
chamber body 112.
[0016] Heating elements 190 and thermocouples 192 control the
temperature of the wafer 120 having deformable layer 122 thereon,
member 160 and other components of the global planarization
apparatus 100 located within chamber body 112.
[0017] In operation, the top clamp ring 188, gasket 186, upper lid
184, and middle lid 182 are removed from the chamber body 112 and
the press plate 130 lifted from lower lid 180. The bellows 140 is
deflated and rigid plate 150 is seated on stand off brackets 142.
The wafer 120 is placed on the flexible member 160 with the side of
the wafer 120 opposite the deformable layer 122 in contact with
flexible member 160. The press plate 130 is mounted on the lower
lid 180 and the middle lid 182 and upper lid 184 are installed and
tightened using gasket 186 and top clamp ring 188 sealing press
plate 130 between top clamp ring 188 and lower lid 180. The
temperature of member 160, press plate 130, wafer 120 having
deformable layer 122 thereon, and rigid plate 150 are adjusted
through the use of heating elements 190 monitored by thermocouples
192 to vary the deformation characteristics of the deformable layer
122 of wafer 120. Chamber body 112 is evacuated through port 119 to
a desired pressure.
[0018] A pressure differential is established between the interior
and exterior of the bellows 140, whether by pressurizing or by
venting, when the chamber body 112 having been evacuated thereby
drives rigid plate 150, member 160, and wafer 120 toward press
plate 130 and brings deformable layer 122 of wafer 120 into
engagement with pressing surface 132 of press plate 130. Upon
engagement of wafer 120 with press plate 130, the continued
application of force will deform the flexible member 160 which, in
turn, serves to close lift pin penetrations 166 and distribute the
force to ensure the wafer 120 experiences uniform pressure on its
surface of deformable layer 122. After the wafer 120 has been in
engagement with pressing surface 132 for sufficient time to cause
its surface of deformable layer 122 to globally correspond to the
pressing surface 132, the surface of deformable layer 122 is
hardened or cured. The pressure is released from the bellows 140
thereby retracting wafer 120, member 160, and rigid plate 150 from
the press plate 130. The downward movement of rigid plate 150 will
be terminated by its engagement with stand off brackets 142.
[0019] Once the rigid plate 150 is fully retracted, the vacuum is
released in chamber body 112. Lift pins 170 are moved through lift
pin penetrations 156 in the rigid plate 150 and lift pin
penetrations 166 in the member 160 to lift wafer 120 off the member
160. The top clamp ring 188, gasket 186, upper lid 184, middle lid
182, and press plate 130 are removed and the wafer 120 is removed
off lift pins 170 for further processing.
[0020] Once the wafer is removed, it will be subjected to an etch
to establish the planar surface at the desired depth. A system used
or depicted in FIG. 1 provides an optimal method of deforming a
flowable, curable material to form a generally planarized surface.
However, the method is still subject to yielding a wafer surface
with irregularities therein, and the need for the subsequent etch
to define the desired surface height will still result in
undesirable transfer and possible enlargement of any such surface
irregularities.
[0021] Conventional chemical mechanical planarization processes are
used to planarize layers formed on wafer substrates in the
manufacture of integrated circuit semiconductor devices. Typically,
a chemical mechanical planarization (CMP) process planarizes a
non-planar irregular surface of a wafer by pressing the wafer
against a moving polishing surface that is wetted with a chemically
reactive, abrasive slurry. The slurry is usually either basic or
acidic and generally contains alumina or silica abrasive particles.
The polishing surface is usually a planar pad made of a relatively
soft, porous material, such as a blown polyurethane, mounted on a
planar platen.
[0022] Referring to drawing FIG. 2, a conventional chemical
mechanical planarization apparatus is schematically illustrated. A
semiconductor wafer 112 is held by a wafer carrier 111. A soft,
resilient pad 113 is positioned between the wafer carrier 111 and
the wafer 112. The wafer 112 is held against the pad 113 by a
partial vacuum. The wafer carrier 111 is continuously rotated by a
drive motor 114 and is also designed for transverse movement as
indicated by the arrows 115. The rotational and transverse movement
is intended to reduce variability in material removal rates over
the surface of the wafer 112. The apparatus further comprises a
rotating platen 116 on which is mounted a polishing pad 117. The
platen 116 is relatively large in comparison to the wafer 112, so
that during the chemical mechanical planarization process, the
wafer 112 may be moved across the surface of the polishing pad 117
by the wafer carrier 111. A polishing slurry containing a
chemically reactive solution, in which abrasive particles are
suspended, is delivered through a supply tube 118 onto the surface
of the polishing pad 117.
[0023] Referring to drawing FIG. 3, a typical polishing table is
illustrated in top view. The surface of the polishing table 1 is
precision machined to be flat and may have a polishing pad affixed
thereto. The surface of the table rotates the polishing pad past
one or more wafers 3 to be polished. The wafer 3 is held by a wafer
holder, as illustrated hereinbefore, which exerts vertical pressure
on the wafer against the polishing pad. The wafer holder may also
rotate and/or orbit the wafer on the table during wafer
polishing.
[0024] Alternately, the table 1 may be stationary and serve as a
supporting surface for individual polishing platens 2, each having
their own individual polishing pad. As illustrated in U.S. Pat. No.
5,232,875, each platen may have its own mechanism for rotating or
orbiting the platen 2. A wafer holder will bring a wafer in contact
with the platen 2 and an internal or external mechanism to the
wafer holder may be used to also rotate the wafer during the
polishing operation. In a polishing table having multiple
individual platens, each platen must be precision machined.
[0025] The wafers 3 are typically stored and transported in wafer
cassettes which hold multiple wafers. The wafers 3 or wafer holders
are transported between the wafer cassettes and the polishing table
1 using the wafer transport arm 4. The wafer transport arm 4 will
transport the wafers 3 between the polishing table and the stations
5, which may be wafer cassette stations or wafer monitoring
stations.
[0026] The polishing characteristics of the polishing pad will
change during use as multiple wafers 3 are polished. The glazing or
changing of the polishing characteristics will affect the
planarization of the surface of the wafers 3 if the pads are not
periodically conditioned and unglazed. The pad conditioner 6 is
used to periodically unglaze the surface of the polishing pad. The
pad conditioner 6 has a range of motion which allows it to come in
contact with the individual pads and conduct the periodical
unglazing and then to move to its rest position.
[0027] The pressure between the surface of the wafer to be polished
and the moving polishing pad may be generated by either the force
of gravity acting on the wafer and the wafer carrier or a
mechanical force applied to the wafer surface. The slurry may be
delivered or injected through the polishing pad onto its surface.
The planar platens may be moved in a plane parallel to the pad
surface with either an orbital, fixed-direction vibratory, or
random direction vibratory, motion.
[0028] While a chemical mechanical planarization process is an
effective process to planarize the surface of a wafer, variations
in height on the surface to be planarized by the chemical
mechanical planarization process, although minimized through the
chemical mechanical planarization process, will often not be
completely removed to yield an optimally planar surface. As is well
known in the art, the chemical mechanical planarization process
polishing pad will deform, or "dish," into recesses between
structures of the surface of the wafer. The structure spacing on
the wafer which will yield this "dishing" is clearly a function of
various factors, such as the pad composition, the polishing
pressure, etc. This pad "dishing" will clearly lead to less than
optimal planarization of the surface of the wafer. Further, the
surface irregularities extending into or down to the wafer surface
being planarized tend to collect slurry, thereby causing such areas
of the wafer to be subjected to the corrosive effects of the slurry
longer than other areas of the wafer surface which do not collect
the slurry.
[0029] To help minimize polishing pad deformation (dishing) caused
by surface irregularities formed by the integrated circuit
components on the wafer surface, dummy structures have also been
included on the wafer surface in an attempt to provide a more
uniform spacing of structures on the wafer surface. While the use
of such dummy structures will often be useful, the ultimate result
is also highly dependent upon the later chemical mechanical
planarization process conditions.
[0030] Alternately, a dry isotropic etching process may be used to
etch the surface on a wafer for planarization to facilitate
planarization of the wafer surface irregularities, rather than use
a chemical mechanical planarization process.
[0031] Therefore, a need exists to reduce the surface
irregularities on a wafer before a planarization process, such as a
chemical mechanical planarization process or a dry etching process,
to facilitate planarization of the wafer surface irregularities by
such a process.
SUMMARY OF THE INVENTION
[0032] The present invention relates to the manufacturing of
semiconductor devices. More particularly, the present invention
relates to an improved method and mechanism using a resilient
flexible material member during wafer processing for the global
planarization of surfaces in the manufacturing of semiconductor
devices. The present invention comprises an improved method and
apparatus for the global planarization of a deformable surface of a
wafer using a resilient flexible material member under the wafer,
and, if desired, a flexible planar interface material prior to the
planarization of the wafer using either an etching planarization
method on the wafer or a chemical mechanical planarization method
on the wafer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a side view of a global planarization
apparatus;
[0034] FIG. 2 is an illustration of a conventional rotational
chemical mechanical planarization apparatus;
[0035] FIG. 3 is an illustration of a top view of a polishing table
of a conventional rotational chemical mechanical planarization
apparatus;
[0036] FIG. 4 is a cross-sectional view of a portion of a wafer
substrate having electrical circuit components formed thereon and a
coating thereover;
[0037] FIG. 5 is a cross-sectional view of a portion of a wafer
substrate having electrical circuit components formed thereon, a
coating thereover, a deformable coating, a portion of a flat
pressing member, a resilient flexible material member having a
substantially uniform thickness and having different density and
resiliency portions thereof, and flexible planar interface material
used in the present invention;
[0038] FIG. 6 is a cross-sectional view of a portion of a wafer
substrate having electrical circuit components formed thereon, a
coating thereover, a deformable coating, a portion of a flat
pressing member, a resilient flexible material member having a
thicker thickness in the center thereof as compared to the
periphery thereof, and flexible planar interface material used in
the present invention;
[0039] FIG. 7 is a cross-sectional view of a portion of a wafer
substrate having electrical circuit components formed thereon, a
coating thereover, a deformable coating, a portion of a flat
pressing member, a resilient flexible material member having a
thicker thickness in the center thereof as compared to the
periphery thereof, flexible planar interface material used in the
present invention and having different density and resiliency
portions thereof, and flexible planar interface material used in
the present invention;
[0040] FIG. 8 is a cross-sectional view of a portion of a wafer
substrate having electrical circuit components formed thereon, a
coating thereover, a deformable coating, a portion of a flat
pressing member, a resilient flexible material member having a
substantially uniform thickness and having a substantially uniform
density and resiliency throughout, and flexible planar interface
material used in the present invention;
[0041] FIG. 9 is a cross-sectional view of a portion of a wafer
substrate having electrical circuit components formed thereon, a
coating thereover, a deformable coating after the deformation
thereof by the flat pressing member, flexible planar interface
material and process of the present invention;
[0042] FIG. 10 is a cross-sectional view of a portion of a wafer
substrate having electrical circuit components formed thereon and a
coating material between the electrical circuit components after
the planarization thereof;
[0043] FIGS. 11A and 11B describe the process flow of the improved
chemical mechanical planarization process of the present invention
as illustrated in FIG. 7;
[0044] FIG. 12 is a quarter cross-sectional view of an embodiment
of a press lid assembly for a press of the present invention to be
used in the method of the present invention;
[0045] FIG. 13 is a cross-sectional view of the present invention
installed on a chamber for planarizing a deformable surface on a
wafer.
[0046] The present invention will be better understood when the
drawings are taken in conjunction with the description of the
present invention hereafter.
DESCRIPTION OF THE INVENTION
[0047] Referring to drawing FIG. 4, a portion of a wafer substrate
20 is illustrated having portions of electrical circuit components
22 formed thereon and a coating of material 24, typically a
metallic material, a semiconductor material, or an insulating
material 24, covering the electrical circuit components 22 and
portions of the wafer substrate 20 located between the electrical
circuit components 22. As illustrated, the portions of the
electrical circuit components 22 are formed having upper surfaces
26 thereon while the coating of insulating material 24 is formed
having an irregular non-planar surface 28 extending over the
surfaces 26 of the electrical circuit components 22. The insulating
coating 24 typically comprises an insulating oxide or other
dielectric material and may include a plurality of layers of such
insulating or other types of material, as desired. In this
instance, for convenience, the insulating material 24 is
illustrated covering the wafer substrate 20 and the electrical
circuit components 22 thereon regardless of the number of layers
thereof.
[0048] It can be easily seen that if only portions of the surface
28 of insulating material 24 is removed for the formation of
additional electrical circuit components, the non-planar surface of
the insulating material 24 would cause masking and etching problems
as the masking of the insulating material 24, as well as the
etching thereof, would not be uniform. Therefore, the surface 28
must be globally planarized to facilitate further electrical
circuit component formation.
[0049] At this juncture, if a conventional chemical mechanical
planarization process is used on the wafer substrate 20, the
surface of the wafer will be subjected to a reactive slurry and one
or more polishing pads will be used in the process in an attempt to
form a planar surface on the insulating material 24 covering the
electrical circuit components 22. Some of the problems associated
with such a conventional chemical mechanical planarization process
are that the reactive slurry is unevenly distributed about the
wafer substrate 20 and the particulates removed from the substrate
20 and insulating material 24 during the polishing process may
become lodged in the polishing pad forming a glaze thereon, thereby
affecting the rate of removal by the pad and causing the polishing
pad to unevenly remove material during the process. As the chemical
mechanical planarization process begins by polishing an irregular
surface on the wafer, such surface causes the deformation of the
polishing pad (dishing), thereby further inducing irregularities
not initially present in the surface being polished. The induced
irregularities of the surface of the wafer during the chemical
mechanical planarization of the wafer surface are caused by the
dishing of the polishing pad from the force applied thereto and the
deformation of the pad by surface areas of the wafer. Therefore,
before starting a chemical mechanical planarization process of the
surface of a wafer, it is desirable to have the surface to be
planarized as nearly planar as possible to help ensure the even
removal of material therefrom and to help eliminate the deformation
of the polishing pad(s) being used to thereby, in turn, help
minimize any surface irregularities being introduced into the
surface being planarized by such pad deformation.
[0050] Similarly, if a conventional dry etching planarization
process in a conventional etcher is used on the wafer substrate 20,
the surface of the wafer will be subject to a reactive process by
the gases used in the etching process in an attempt to form a
planar surface on the insulating material 24 covering the
electrical circuit components 22. Some of the problems associated
with such a conventional dry etching planarization process are if
the surface 28 of the insulating material 24 is not planar and is
deformed, the isotropic etching of the insulating material 24 will
result in a non-planar surface, the reactive gases may be unevenly
distributed about the wafer substrate 20, thereby further causing
uneven etching of the surface 28 of the insulating material 24 on
the substrate 20 resulting in an increased non-planar surface 28,
and any irregularities in the surface of the substrate 20 will be
etched at different rates by the gases used in the dry etching
planarization process causing the same or greater irregularities in
the surface of the substrate 20. Simply stated, if the surface 28
of the insulating material 24 is non-planar or bumpy, the isotropic
etching thereof will result in a non-planar or bumpy surface
28.
[0051] Referring to drawing FIG. 5, the improved planarization
process of the present invention is illustrated in relation to a
wafer substrate 20 having electrical circuit components 22 thereon
and a coating of insulating material 24 thereover. In the improved
planarization process of the present invention, prior to the
initiation of the planarization of the substrate 20, electrical
circuit components 22 and insulating material 24, a layer of
deformable material 30 is coated or deposited over the insulating
material 24. The deformable material 30 may be of any suitable type
material that readily flows over the surface 28 of the insulating
material 24 and that is subsequently solidified through curing or
hardening or other type of solidification. Alternately, the
deformable material 30, in some instances, may be a readily
deformable metal capable of being deformed under low temperature
and low pressure which may be readily deposited over the insulating
material 24 through well-known techniques and processes. Whatever
the type of deformable material 30, the deformable material 30 is
applied over the insulating material 24 to any desired depth but is
typically applied in a thickness greater than the thickness of the
surface typography of the wafer. The thickness of the deformable
material 30 initially applied to the wafer depends upon the type of
material selected for such use, and the dimensions of the surface
irregularities, etc. After the application of the layer of
deformable material 30 to the insulating material 24 and before the
deformable material 30 has cured, hardened or solidified to the
point which it is not capable of being deformed, an object 32
having a flat, planar surface 34 thereon and a flexible planar
interface material 40, which is fixed or immovable with respect to
the substrate 20, are forced under pressure into the deformable
material 30 to form a flat, planar surface 36 thereon and is kept
in contact with the deformable material 30 while the deformable
material 30 cures, hardens, or solidifies. The object 32 may be of
any well-known suitable material, such as an optical grade or
optical quality quartz disc-shaped object, glass disc-shaped
object, ceramic disc-shaped object, stone disc-shaped object or any
desired material disc-shaped object having a desired flat, planar
surface thereon which may be used to be pressed into the deformable
material 30 to form a flat, planar surface 36 thereon. If desired,
the object 32 may be tailored to meet process requirements of the
desired range of pressure to be applied to the deformable material
30 and the method of curing, hardening or solidifying the
deformable material 30. Further, if desired, the surface 34 on the
object 32 may have a shape other than a flat, planar surface 34,
such as either a concave surface, convex surface, concave and
convex surface or any type desired surface suitable in a chemical
mechanical planarization process. Additionally, the surface 34 of
the object 32 may be coated with a suitable release agent coating
to facilitate its removal from the flexible planar interface
material 40 after the curing, hardening or solidification of the
deformable material 30. The flexible planar interface material 40
may be any suitable material, such as planar Teflon.TM. sheet
material or the like, having a high degree of planarity between the
upper and lower surfaces thereof. Alternately, the flexible planar
interface material 40 may comprise a flexible planar sheet of metal
or a flexible planar sheet of polymeric material, etc. The flexible
planar interface material 40 may either allow the transmission of a
broad spectrum of light therethrough or be opaque to a broad
spectrum of light. If the flexible planar interface material is of
Teflon.TM., it is preferable that the flexible planar interface
material 40 have a thickness in the range of 0.010 inches to 0.040
inches. It is further preferable that the thickness of the
Teflon.TM. flexible planar interface material 40 be approximately
0.010 inches. The flexible planar interface material 40 is used to
facilitate the release of the object 32 from the surface 36 of the
deformable material 30 after the curing, hardening or
solidification thereof. If desired, the flexible planar interface
material 40 may also be coated with a suitable release agent
coating to facilitate its removal from the deformable material 30
after the curing, hardening, or solidification thereof and/or to
facilitate its removal from the object 32. The substrate 20 is
preferably removed from the flexible planar interface material 40
by applying fluid under pressure, preferably a burst of fluid under
pressure, between the object 32 and the flexible planar interface
material 40 to cause the substrate 20 to be removed therefrom by
the fluid under pressure, causing the flexible planar interface
material 40 to either flex, ripple, deform, or bow, or flex,
ripple, deform, and bow as the fluid flows into the space between
the object 32 and the flexible planar interface material 40. After
the substrate 20 is removed from the flexible planar interface
material 40, a vacuum may be applied to the space between the
object 32 and the flexible planar interface material 40 to cause
the flexible planar interface material 40 to engage the surface 34
of object 32.
[0052] The deformable material 30 may be any suitable well-known
organic type, such as monomers, monomer mixtures, oligomers, and
oligomer mixtures that are solidified through curing. Alternately,
the deformable material 30 may be any suitable type epoxy resin
which may be cured using an acid catalyst.
[0053] The object 32 and flexible planar interface material 40 is
kept through the application of suitable pressure thereto,
application of pressure to the wafer substrate 20, or the
application of pressure to both the object 32 and the wafer
substrate 20 in engagement with the deformable material 30 until
such material has hardened or solidified to form a permanent flat,
planar surface 36 thereon being the mirror image of the flat,
planar surface 34 on the object 32. At such time, the object 32 and
the flexible planar interface material 40 are removed from
engagement with the deformable material 30 using the application of
fluid under pressure to the space between the object 32 and the
flexible planar interface material 40.
[0054] Also illustrated in drawing FIG. 5, is a flexible resilient
material member 50, having surfaces 52 and 54 thereon, comprising a
suitably shaped member compatible with the wafer substrate 20,
formed of resilient material which will deform under an applied
force to distribute the applied force from the object 32 to the
deformable material 30, even if the surface 34 of object 32, the
surfaces of flexible planar interface material 40, illustrated as
surfaces 42 and 44, and the surface 36 of deformable material 30 on
the wafer substrate 20 are not substantially parallel to each other
or, alternately, when thickness variations locally exist within
either the wafer 20, electrical circuit components 22, insulating
material 24, object 32, and/or flexible resilient material member
50. It is preferred that the flexible resilient material member 50
be thermally stable and resistant to the temperature ranges of
operation experienced during the pressing by object 32 and flexible
planar interface material 40 and that the flexible resilient
material member 50 be formed from a low viscosity and low durometer
hardness material. In this manner, the flexible resilient material
member 50 serves to compensate for the variations in the thickness
of the substrate 20, electrical circuit components 22, insulating
material 24, deformable material 30, object 32, and flexible planar
interface material 40 as well as compensating for any non-parallel
surfaces on the object 32, flexible planar interface material 40,
wafer 20 or the substrate or support 60 (150 in drawing FIG. 13) on
which the wafer 20 is supported during the pressing of object 32 to
form planar surface 36 on the deformable material 30 prior to
beginning the planarization process thereafter. The preferable
manner in which the insulating coating 24 on a wafer 20 is to be
globally planarized by etching or chemical mechanical planarization
to have a globally flat, planar surface 28 is to use the global
planarization process and apparatus described herein. As
illustrated in drawing FIG. 5, the flexible resilient material
member 50 includes different portions thereof having different
hardness resilient flexible material therein to help evenly
distribute the deformable material 30 across the surface of the
wafer 20 during the global planarization process. For instance, the
central portion 55 of the resilient flexible material member 50 is
formed having the greatest hardness, the first annular area 57
surrounding the central portion 55 is formed having the next
greatest hardness and is softer than the central portion 55, and
the second annular area 59 surrounding the first annular area 57 is
formed having a lesser hardness than either the first annular area
57 and the central portion 55. In this manner, when the central
portion 55 of the resilient material member 50 contacts the
deformable material 30, the central portion 55 does not compress
initially to cause the deformable material 30 to have a force
applied thereto to cause the deformable material 30 to flow, move
and/or deform radially outwardly from the center portion of the
wafer 20 until the central portion 55 of the member 50 is
compressed sufficiently when the first annular area 57 has
sufficient force applied thereto to cause the compression thereof
when the second annular portion 59 is compressed. In this manner,
the deformable material 30 is caused to flow and/or deform radially
outwardly during the initial compression of the resilient flexible
material member 50 to help ensure a substantially constant
thickness of the deformable material 30 over the wafer 20.
Alternately, the resilient flexible material member 50 may be
formed having substantially the same thickness throughout and the
same durometer hardness of material. The resilient flexible
material member 50 exhibits a varying rate or variable rate of
deflection under the application of a force thereto, as the central
portion 55 deflects less than the first annular area 57 which
deflects less than the second annular area 59 when a force is
applied to the member 50.
[0055] Referring to drawing FIG. 6, as illustrated, the resilient
material member 50 includes a thicker central portion than the
perimeter portion thereof to help evenly distribute the deformable
material 30 across the surface of the wafer 20 during the global
planarization process. For instance, the central portion 50' of the
resilient flexible material member 50 is formed having the greatest
thickness while the annular area 50" surrounding the central
portion 50' is formed having a lesser thickness. The resilient
material member 50 is formed of the same material but having a
thicker central portion than the perimeter portion. In this manner,
when the central portion 50' of the resilient material member 50
contacts the deformable material 30, the central portion causes the
deformable material to have a force applied thereto to cause the
deformable material 30 to flow and/or be deformed radially
outwardly from the center portion of the wafer 20 until the central
portion of the member 50 is compressed sufficiently when the
annular perimeter portion 50" has sufficient force applied thereto
to cause the compression thereof to deform the deformable material
30. In this manner, the deformable material 30 is caused to flow,
move, and/or deform radially outwardly during the initial
compression of the resilient flexible material member 50 to help
ensure a substantially constant thickness of the deformable
material 30 over the wafer 20. The resilient flexible material
member 50 exhibits a varying rate or variable rate of deflection
under the application of a force thereto, as the central portion
50' deflects more than the annular perimeter portion 50" when a
force is applied to the member 50.
[0056] Referring to drawing FIG. 7, as illustrated, the resilient
material member 50 includes different portions thereof having
different thickness and hardness resilient flexible material
therein to help evenly distribute the deformable material 30 across
the surface of the wafer 20 during the global planarization
process. For instance, the central portion 55' of the resilient
flexible material member 50 is formed having the greatest thickness
and hardness, the first annular area 57' surrounding the central
portion 55 is formed having the next greatest thickness and
hardness and is softer than the central portion 55, and the second
annular area 59' surrounding the first annular area 57' is formed
having a lesser thickness and hardness than either the first
annular area 57' and the central portion 55'. In this manner, when
the central portion 55' of the resilient material member 50
contacts the deformable material 30, the central portion does not
compress initially to cause the deformable material to have a force
applied thereto to cause the deformable material 30 to flow and/or
deform radially outwardly from the center portion of the wafer 20
until the central portion of the member 50 is compressed
sufficiently when the first annular area 57' has sufficient force
applied thereto to cause the compression thereof when the second
annular area 59' is compressed. In this manner, the deformable
material 30 is caused to flow, move, and/or deform radially
outwardly during the initial compression of the resilient flexible
material member 50 to help ensure a substantially constant
thickness of the deformable material 30 over the wafer 20. The
resilient flexible material member 50 exhibits a varying rate or
variable rate of deflection under the application of a force
thereto as the central portion 55' deflects more than the first
annular area 57' which deflects more than the second annular area
59' when a force is applied to the member 50.
[0057] Referring to drawing FIG. 8, the resilient flexible material
member 50 is formed having a substantially uniform thickness and
hardness. The resilient flexible material member 50 is similar to
that illustrated in drawing FIG. 5 except it is formed of the same
durometer hardness material.
[0058] Referring to drawing FIG. 9, before the planarization
process, either by a dry chemical etching process or a chemical
mechanical planarization process, of the coatings 28 and 30 on the
circuits 22 on the wafer 20 commences, the wafer substrate 20
having electrical circuit components 22 and insulating coating 24
thereon is illustrated having the deformable material 30 having a
flat, planar surface 36 thereon providing a global flat, planar
surface 36 on the wafer substrate. As illustrated, the global
surface 36 on the deformable material 30 is a flat, planar surface
from which a planarization process is to begin on the wafer
substrate 20. In this manner, a conventional well-known
planarization process as described hereinbefore can be used to form
flat planar surfaces on the insulating material 24. By starting
with a globally flat, planar surface 36 on the deformable material
30, any deformation of the pad 117 (FIG. 2) is minimized if a
chemical mechanical planarization process is used. Also, any
non-uniform planarization which may occur due to the uneven
distribution of the chemical reactive solution and abrasives
included therein or material particles from the surfaces being
planarized being collected or present in the pad 117 resulting from
surface irregularities is minimized. In this manner, by starting
the chemical mechanical planarization process from a globally flat,
planar surface 36 of the deformable material 30 as the chemical
mechanical planarization process is carried out, the surfaces of
the layers being planarized remain flat and planar because the pad
117 is subjected to more uniform loading and operation during the
process. This is in clear contrast to the use of a chemical
mechanical planarization process beginning from an irregular
non-planar surface as is typically carried out in the prior art.
Similarly, if a dry chemical etching planarization process is used,
by starting the dry chemical etching process from a globally flat,
planar surface 36 of the deformable material 30, as the dry
chemical etching planarization process is carried out, the surfaces
of the layers being planarized remain flat and planar because the
chemical gases used in the dry etching process react at the same
rate on the flat and planar global surfaces of the coatings 24 and
30, thereby keeping the surfaces globally flat. This is in clear
contrast to the use of a chemical dry etching process beginning
from an irregular non-planar surface as is typically carried out in
the prior art.
[0059] Referring to drawing FIG. 10, illustrated is a wafer
substrate 20, electrical circuit components 22 and insulating layer
24 which have been planarized using the improved planarization
process of the present invention. As illustrated, a flat, planar
surface 28' has been formed through the use of the planarization
process using the object 32 and flexible innerface material 40 of
the present invention as described hereinbefore with a subsequent
planarization process, such as a chemical mechanical planarization
process or a dry chemical etching process to form the flat planar
surface 28' of the insulating material 24.
[0060] Referring to drawing FIGS. 11A and 11B, the improved
chemical mechanical planarization process of the present invention
as described hereinbefore is illustrated in a series of process
steps 202 through 218.
[0061] In process step 202, a wafer substrate 20 is provided having
electrical circuitry components 22 formed thereon and an insulating
material coating 24 covering the components 22 and portions of the
wafer substrate 20.
[0062] In process step 204, a coating of deformable material 30
which is uncured, unhardened, or unsolidified at the time of
application is applied to the coating of insulating material 24 to
cover the same.
[0063] Next, in process step 206, an object 32 having a flat planar
surface 34 thereon is provided for use.
[0064] In process step 208, the surface of deformable material 30
is contacted by the flat, planar surface 34 of the object 32 while
the wafer substrate 20 is supported on the resilient flexible
material member 50.
[0065] In process step 210, a predetermined level of pressure is
applied at a predetermined temperature level to the deformable
material 30. The pressure may be applied to either the object 32
having the flexible planar material interface 40 between the object
32 and substrate 20, the substrate 20, or both, etc. At the time
the pressure is applied to the deformable material 30, the
resilient flexible material member 50 helps cause the flow and/or
deformation of the deformable material 30 radially outwardly to
form a uniform layer of deformable material on the substrate wafer
20.
[0066] In process step 212, flat, planar surface 34 of object 32
having flexible planar material interface 40 thereover forms a
flat, planar surface 36 on the deformable material 30.
[0067] In process step 214, while the flat, planar surface of the
flexible planar material interface 40 and the object 32 engages the
deformable material 30 thereby forming the flat, planar surface 36
thereon, the deformable material 30 is cured, hardened, or
solidified to cause the permanent formation and retention of the
flat, planar surface 36 on the deformable material 30.
[0068] In process step 216, the object 32 and flexible planar
interface material 40 are removed from engagement with the
deformable material 30 after the curing, hardening or
solidification thereof to retain the flat, planar surface 36
thereon by the sudden application of fluid pressure, such as a
burst of fluid pressure to the space between the object 32 and
flexible planar interface material 40. Subsequent to the removal of
the flexible planar interface material 40 from the deformable
material 30 of substrate 20, a vacuum may be applied to the space
between the object 32 and flexible planar interface material 40 to
cause the flexible planar interface material 40 to engage the
surface 34 of object 32. At this time, the resilient flexible
material member 50 is removed from contact with and support for the
wafer substrate 20.
[0069] In process step 218, the wafer substrate 20 having
electrical circuit components 22, insulating coating 24, and cured,
hardened, or solidified deformable coating 30 thereon, is subjected
to a suitable planarization process until the upper surfaces 26' of
the electrical circuit components and surface 28' of the insulating
material 24 are a concurrent common flat, planar surface extending
across the wafer substrate 20 (see FIG. 10).
[0070] In this manner, when the improved process of chemical
mechanical planarization of the present invention is used, the
resulting planarized surface on the wafer substrate is globally
planar or more planar since the process started from a globally
flat, planar surface and the chemical mechanical planarization
process reaches a successful conclusion more quickly.
[0071] Alternately, the wafer substrate 20 having electrical
circuit components 22, insulating coating or material 24, and
cured, hardened, or solidified deformable coating 30 thereon, is
subjected to a suitable dry isotropical etching process in a
suitable type plasma etcher until the upper surfaces 26' of the
electrical circuit components 22 and surface 28' of the insulating
material 24 are substantially a concurrent common flat, planar
surface extending across the wafer substrate 20 (see FIG. 10).
[0072] Referring to drawing FIG. 12, a lid assembly 300 is
illustrated that may be used with an apparatus such as described in
drawing FIGS. 1 and 13 for the planarization of a coating on the
surface of a semiconductor wafer.
[0073] Referring to drawing FIG. 12, a first embodiment of the
present invention is illustrated. A wafer press lid assembly 300 is
illustrated for use in the global planarization apparatus and
process of the present invention. The lid assembly 300 comprises an
upper lid 302, lid clamp 304, middle lid 306, lower lid 308, main
chamber 310, object clamp 316, optical flat object 32, interface
clamp 382, flexible planar interface material 40, upper annular
seal 312 which sealingly engages upper surface 330 of lid clamp 304
and the lower surface 324 of upper lid 302, lower annular seal 314
which sealingly engages outer annular surface 356 of middle lid 306
and the lower surface 334 of lid clamp 304, and annular seal 318
which sealingly engages the outer diameter of optical flat object
32 and the frusto-conical annular surface 395 of object clamp 316.
The annular seals 312 and 314 may be any suitable seal type
material, such an annular Teflon.TM. material type seal. The
annular seal 318 may be any suitable type seal, such as an
elastomeric o-ring type seal, a silicon o-ring type seal, etc.
[0074] The upper lid 302 comprises a generally cylindrical annular
member having an upper surface 320, cylindrical inner surface 322,
lower surface 324, cylindrical outer surface 326, and a plurality
of apertures 328 therein which contain a plurality of threaded
fasteners 329 extending therethrough to retain the upper lid 302 in
position secured to the lid clamp 304.
[0075] The lid clamp 304 comprises a generally cylindrical annular
member having an upper surface 330, inner cylindrical surface 332,
lower surface 334, outer cylindrical surface 338, and a plurality
of threaded apertures 340 therein, each aperture 340 receiving a
portion of a threaded fastener 329 extending therein to retain the
lid clamp 304 in position with respect to the upper lid 302.
[0076] The middle lid 306 comprises a generally cylindrically
shaped annular member having an upper surface 342, frusto-conical
annular inner surface 344 which sealingly engages a portion of
annular seal 318, inner cylindrical surface 346, first cylindrical
annular surface 348 having a plurality of threaded blind apertures
350 therein, first vertical outer diameter surface 352, second
cylindrical annular surface 354, and second vertical outer diameter
surface 356. The middle lid 306 further includes at least one
aperture 358, alternately a plurality of apertures, extending
therethrough from the second vertical outer diameter surface 356 to
the inner cylindrical surface 346 to allow a suitable gas or other
fluid to flow therethrough, the at least one aperture 358 having a
suitable connector 359 connected thereto for connection to a supply
of gas under pressure or fluid under pressure. The middle lid 306
further includes a plurality of threaded apertures 357 therein,
each aperture 357 receiving and retaining a portion of threaded
fastener 329 therein to retain the middle lid 306 to the upper lid
302.
[0077] The lower lid 308 comprises a generally annular cylindrical
member having an upper surface 360 having an annular seal groove
362 therein having, in turn, annular o-ring seal 364 therein, first
vertical inner cylindrical surface 366, inner annular surface 368
having a plurality of blind apertures 370 therein to provide
clearance for the heads of threaded fasteners 393 therein, second
vertical inner cylindrical surface 372, bottom or lower surface 374
having annular seal groove 376 therein having, in turn, annular
o-ring seal 378 therein, and outer diameter cylindrical surface
380. The lower lid 308 further includes a plurality of apertures
381 therein extending from upper surface 360 to lower surface 374,
each aperture containing a portion of a threaded fastener 383
therein to secure the lower lid 308 to the chamber 310. The annular
seal grooves 362 and 376 contain a suitable annular o-ring type
seal 364 and 378 therein, respectfully, such as an elastomeric
o-ring type seal, which sealingly engages the second annular
cylindrical surface 354 and upper surface of chamber 310.
[0078] The interface clamp 382 comprises a generally cylindrical
annular member having an upper surface 384, inner cylindrical
surface 386, lower surface 388, and outer cylindrical diameter 390.
The interface clamp 382 further includes a plurality of apertures
392 therein, each aperture having a portion of threaded fastener
393 extending therethrough to retain the interface clamp 382
connected to the middle lid 306 and to retain a portion of the
flexible planar interface material 40 between the interface clamp
382 and the first annular cylindrical surface 348 of the middle lid
306.
[0079] The chamber 310 comprises any suitably shaped chamber
capable of holding a substrate 20 therein for the planarization of
the deformable coating 30 on the surface thereof using the optical
flat object 32 and flexible planar interface material 40, such as a
metal cylindrical annular chamber 310 having a plurality of
threaded blind apertures 311 extending from the upper surface
thereof into the wall of the chamber 310 to receive threaded
portions of the threaded fasteners 383 therein to retain the lower
lid 308 connected thereto when a vacuum is created in the chamber
310. The upper surface of the chamber 310 is suitable for the
annular o-ring seal 378 of lower lid 308 to sealingly engage to
form a suitable pressure and vacuum seal therewith. The chamber may
include a thermocouple and a suitable heater therein, if
desired.
[0080] The object clamp 316 comprises a generally annular
cylindrical member having an upper surface 398, inner diameter
vertical surface 394, frusto-conical annular surface 395 which
sealingly engages a portion of annular seal 318, lower surface 396
which abuts a portion of upper surface 342 of middle lid 306, and
outer diameter surface 397.
[0081] The flexible planar interface material 40 extends across the
bottom surface 34 of the optical flat object 32 by the interface
clamp 382 retaining the material 40 in the lid assembly 300. The
flexible planar interface material 40 may be any suitable type
material, such as a planar Teflon.TM. material, a synthetic resin
polymer, etc., which allows the transmission of light therethrough
which is used to cure, harden, or solidify the deformable coating
30 on the insulating coating 24 on the substrate 20. Alternately,
the flexible planar interface material 40 may be any suitable type
of material, such as a planar Teflon.TM. material, a synthetic
resin polymer, a flexible, planar thin metal material, etc., which
does not need to allow for the transmission of light therethrough
as the material forming the deformable coating 30 hardens, cures,
or solidifies. The flexible planar interface material 40 must have
sufficient strength and thickness to resist any substantial
thinning and/or stretching thereof during use, must have sufficient
flexibility during use to conform to the surface of deformable
coating 30 and allow removal of the substrate 20 from the interface
material 40 after the planarization of the deformable coating 30
and the removal of the interface material 40 from the surface 34 of
the object 32, and must not be subject to any wrinkling thereof
during use, etc. For instance, when using a Teflon.TM. flexible
planar interface material 40, the thickness of the Teflon.TM.
flexible interface material 40 is preferred to be in the range of
0.040 inches thick to 0.005 inches thick for satisfactory use
thereof. A thickness of 0.010 inches has been found to be effective
and preferred for the use of a Teflon.TM. flexible planar interface
material 40. If the thickness of the flexible planar interface
material 40 is too great, the interface material 40 will not flex
sufficiently to allow ready removal of the substrate 20 from the
interface material 40 after the planarization of the deformable
coating 30 on the substrate 20 and will not allow for an effective
planarization of the deformable coating 30 on the substrate 20 as
the interface material 40 will locally deform and deflect.
Alternately, if the flexible planar interface material 40 is too
thin, the interface material 40 will stretch, tear or rip when
subjected to forces during planarization and during the application
of fluid pressure thereto to remove the substrate 20 therefrom.
[0082] The optical flat object 32 may be any suitable type
material, such as an optical grade glass flat or optical quality
glass flat having a cylindrical shape to fit in the clamp assembly
300 in sealing engagement therewith which allows the transmission
of light therethrough which is used to cure, harden, or solidify
the deformable coating 30 on the insulating coating 24 on the
substrate 20. Alternately, if light transmission through the object
32 is not required, the object 32 may be of any suitable type
material having the desired flat surface 36 thereon, such as
ceramic material, stone material, or any material capable of having
the desired flat surface thereon, etc.
[0083] To assist in removing the optical flat object 32 and the
flexible planar interface material 40 from the surface of the
deformable coating 30 on the substrate 20 after the curing,
hardening, or solidification thereof, a pressurized fluid, such as
a suitable gas, is supplied through aperture(s) 358 in the middle
lid 306 into the area between the optical flat object 32 and the
interface material 40 to separate the interface material 40 from
the surface 34 of the object 32 and also, by the flexing of the
interface material 40 to separate the interface material 40 from
the surface 36 of the deformable coating 30 to allow removal of the
substrate 20 from the chamber 310. The pressurized fluid, such as a
gas, may be any suitable gas supplied under pressure, such as
compressed air, nitrogen, etc. If desired, a suitable liquid may be
used rather than a gas, such as water, oil, etc., so long as the
liquid may be readily removed from the area or space between the
surface 34 of object 32 and the flexible planar interface material
40. When the pressurized fluid, such as a gas, is introduced
between the surface 34 of object 32 and the flexible planar
interface material 40, the pressurized fluid is introduced at a
rate, such as in a burst of pressurized fluid, causing the rapid or
very rapid flexing, rippling, or bowing, or flexing, rippling, and
bowing and/or movement of the interface material 40 to cause the
substrate 20 to quickly and suddenly release therefrom and to cause
the interface material 40 to quickly, suddenly release from the
surface 34 of object 32. If desired, release agents may be used to
enhance the release of the substrate 20 from the flexible planar
interface material 40 and to enhance the release of the flexible
planar interface material 40 from the surface 34 of object 32. The
pressurized fluid, such as a gas, should not be introduced into the
space between the surface 34 of object 32 and flexible planar
interface material 40 at such a rate to cause the thinning or
wrinkling of the interface material 40 but, rather, cause the
flexing thereof. An effective manner to remove the substrate 20
from the flexible planar interface material 40 and the flexible
planar interface material 40 from the surface 34 of object 32, is
to supply pressurized fluid, such as a gas, into the space between
the surface 34 of object 32 and the flexible planar interface
material 40 in a burst to cause the substrate 20 to pop, or be
rapidly removed from the interface material 40 and, subsequently,
apply a vacuum to the space between the surface 36 of object 32 and
the flexible planar interface material 40 to cause the interface
material 40 to adhere to the surface 34 of object 32.
[0084] Referring to drawing FIG. 13, the present invention is shown
with a chamber for the planarization of a deformable surface, such
as surface 36 of deformable material 30 on a wafer 20 illustrated
in drawing FIGS. 5 through 9. A chamber 310 as described
hereinbefore, is used with a lid press assembly 300 as described
hereinbefore, to planarize a deformable surface 32 on a wafer 20.
An interface 40 is used between the optical flat object 32 in the
lid assembly and the wafer 20. The wafer 20 is placed on a wafer
support 150 on a lifting apparatus 140, such as described
hereinbefore for the planarization process of deformable surface 36
on wafer 20. A resilient member 160 as described hereinbefore is
included below the wafer 20 on the support 150. The chamber is
subjected to a vacuum using aperture 111 therein. A thermocouple
192 may be included to sense the temperature generated by heater
190 within the chamber.
[0085] It will be understood that changes, additions,
modifications, and deletions may be made to the improved chemical
mechanical planarization process of the present invention, which
are clearly within the scope of the claimed invention.
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